1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)getnetent.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd June 4, 1993 36.Dt GETNETENT 3 37.Os BSD 4.2 38.Sh NAME 39.Nm getnetent , 40.Nm getnetbyaddr , 41.Nm getnetbyname , 42.Nm setnetent , 43.Nm endnetent 44.Nd get network entry 45.Sh LIBRARY 46.Lb libc 47.Sh SYNOPSIS 48.Fd #include <netdb.h> 49.Ft struct netent * 50.Fn getnetent void 51.Ft struct netent * 52.Fn getnetbyname "const char *name" 53.Ft struct netent * 54.Fn getnetbyaddr "unsigned long net" "int type" 55.Ft void 56.Fn setnetent "int stayopen" 57.Ft void 58.Fn endnetent void 59.Sh DESCRIPTION 60The 61.Fn getnetent , 62.Fn getnetbyname , 63and 64.Fn getnetbyaddr 65functions 66each return a pointer to an object with the 67following structure 68containing the broken-out 69fields of a line in the network data base, 70.Pa /etc/networks . 71.Bd -literal -offset indent 72struct netent { 73 char *n_name; /* official name of net */ 74 char **n_aliases; /* alias list */ 75 int n_addrtype; /* net number type */ 76 unsigned long n_net; /* net number */ 77}; 78.Ed 79.Pp 80The members of this structure are: 81.Bl -tag -width n_addrtype 82.It Fa n_name 83The official name of the network. 84.It Fa n_aliases 85A zero terminated list of alternate names for the network. 86.It Fa n_addrtype 87The type of the network number returned; currently only AF_INET. 88.It Fa n_net 89The network number. Network numbers are returned in machine byte 90order. 91.El 92.Pp 93The 94.Fn getnetent 95function 96reads the next line of the file, opening the file if necessary. 97.Pp 98The 99.Fn setnetent 100function 101opens and rewinds the file. If the 102.Fa stayopen 103flag is non-zero, 104the net data base will not be closed after each call to 105.Fn getnetbyname 106or 107.Fn getnetbyaddr . 108.Pp 109The 110.Fn endnetent 111function 112closes the file. 113.Pp 114The 115.Fn getnetbyname 116function 117and 118.Fn getnetbyaddr 119sequentially search from the beginning 120of the file until a matching 121net name or 122net address and type is found, 123or until 124.Dv EOF 125is encountered. 126The 127.Fa type 128must be 129.Dv AF_INET . 130Network numbers are supplied in host order. 131.Sh FILES 132.Bl -tag -width /etc/networks -compact 133.It Pa /etc/networks 134.El 135.Sh DIAGNOSTICS 136Null pointer 137(0) returned on 138.Dv EOF 139or error. 140.Sh SEE ALSO 141.Xr networks 5 142.Pp 143.%T RFC 1101 144.Sh HISTORY 145The 146.Fn getnetent , 147.Fn getnetbyaddr , 148.Fn getnetbyname , 149.Fn setnetent , 150and 151.Fn endnetent 152functions appeared in 153.Bx 4.2 . 154.Sh BUGS 155The data space used by 156these functions is static; if future use requires the data, it should be 157copied before any subsequent calls to these functions overwrite it. 158Only Internet network 159numbers are currently understood. 160Expecting network numbers to fit 161in no more than 32 bits is probably 162naive. 163